In order to analyze the impact of preload on the radiation noise of all ceramic angular contact bearings, 24 uniformly distributed field points were selected in the circumferential direction with a radius of 210mm for analysis. The angle between adjacent field points was 15 ℃, and the distance from each field point to the bearing plane was 50mm. The bearing speed was set to 18000r/min and 24000r/min. The oil supply was set to 0.02ml/min, and the preload Fa was calculated to be 250N, 300N, 350N, 400N, 450N, respectively Radiated noise of all ceramic angular contact bearings at 500N. Make the bearing material, size, and other condition parameters the same as before.